1 Reply Latest reply on Aug 29, 2019 12:27 AM by RakshithM_16

    SWD USB vs. JTAG on CY8C32




      I'm working on a custom board using a CY8C3245LTI-144 and wanted to know more about the progamming interfaces. The datasheet doesn't make it fully clear to me whether or not SWD is available on the USB pins P15[6] and P15[7] by default. Do I need to break out JTAG pins on my board, or can I just break out P1[2] for XRES and use the USB port to program it? Would it be better to use a USB bootloader and use P1[0] and P1[1] for the initial programming/flashing via SWD if I'm planning on creating a USB application?


      Thank you,


        • 1. Re: SWD USB vs. JTAG on CY8C32

          Hello @anra_4352381,


          PSoC 3 supports programming through the SWD interface or JTAG interface. PSoC 3 has two pins that support SWD:  P1[0] SWDIO and P1[1] SWDCK, or P15[6] USB D+ (SWDIO) and P15[7] USB D– (SWDCK) pins. The internal device logic chooses between these pins automatically by detecting clock transition on SWDCK lines after the device comes out of reset. P1[2] can be used for XRES and USB port can be used for SWD programming as all SWD interface programmers support programming using the XRES pin provided the power is externally supplied.


          Although PSoC 3 and 5 supports SWD using USBIO, it is suggested to keep a dedicated SWD 5 pin port or JTAG 10 pin port so that it is compatible with PSoC 4 or 6 (which do not support SWD using USBIO) in case of an upgrade.


          For further details regarding SWD interface hardware connection please refer to '1.2.1 SWD Interface' in Page 5 of 'PSoC 3 Device Programming Specifications.'

          PSoC 3 Device Programming Specifications link - https://www.cypress.com/file/44676/download


          For details regarding using of USBIO as SWD pins refer the Knowledge Based Article 'Serial Wire Debug (SWD) Using USBIO Pins in PSoC® 3 and PSoC 5LP – KBA82881' - https://community.cypress.com/docs/DOC-11978


          For information regarding USB bootloading refer the App Note 'PSoC® USB HID Bootloader' - https://www.cypress.com/file/45376/download



          Rakshith M B